Kahn's USDM 2JZGTE swap thread (aka The "Not Easy" Way)
09-15-16, 01:55 PM
#286
Thanks Ali! It's getting there. It made sense to take care of the ECU and cylinder head now rather than later. Driftmotion quoted me an affordable price for the basic head work and while I told them I wasn't under any deadline and didn't care how long it took them the time ballpark is probably only a few weeks. Then I'll get it shipped to Florida to stay with the engine block.
Hahahaha! What can I say, Gerry... I leave no stone unturned 
It's the same way I approach any kind of project-- not just cars.
No, I think it'll be into spring still before this is anywhere near done. Once I have the cleaned and assembled head back I will slow down and take a break again other than to ship that and a few other parts to Florida for the assembly later. And I will evaluate and work on the wiring harness here-- I just haven't had time to devote to it yet.
With the exception of engine bearings and a gasket kit I have the bottom end prepped. I still have to drill the GE oil pan turbo drain also. And I probably should order new knock sensors, right? Especially if I'll be using the engine in areas with 91 and sometimes 90 (higher altitude) octane?
....
With the original engine setup, however, I am getting more concerned about the rough starting issue. It is very consistent now. Same exact behavior though-- only at cold startup or after cooling down a bit from full operating temperature. Zero misfires or moments of hesitation during operation. Only once has the problem occurred after startup: when I let the engine idle for about 25 minutes straight waiting to put the rear wheels on a dyno for a smog pre-test a few months back. I shut the engine off and restarted and it fired right back up. It's never done it again since.
Having replaced so many obvious parts already I am still suspecting either the original fuel pump, original fuel ECU or perhaps one of the replaced remanufactured injectors sticking. The problem always clears up before I am able to touch all six injectors with my stethoscope when the engine is starting from cold and has the rough idle. I think I will begin testing them in specific blocks of threes or twos each morning to give myself enough of a time window to positively rule out the good ones. If they all turn out to be good then I can't imagine it being anything else other than the fuel ECU or fuel pump.
I did try the fuel ECU bypass a few months ago but it seemed to make no difference. I think I will try it again just to be sure.
I have that new OEM TT pump. I could just do that and the +12V w/relay mod now if the injectors all check out OK. Have to look up the procedures you guys have laid out for the wiring.
I prefer to leave this issue alone but I also don't want the car to strand me if whatever this is does make something fail.
Stop asking me to fix more things, car! You're getting a whole engine
...
It was also recommended to me at Driftmotion that I might want to look into a steel 1-piece driveshaft to replace my MKIII front and SC300 rear shaft setup since I did have some tight initial spline clearance when it first went in requiring me to remove the rear metal shield on the R154's output area. I haven't had the original symptom related to that in three years so I haven't worried about it but maybe it's sound advice.
Can't do it now but I may well in the new year.
The guy in the picture is in serious dilemma ....
Saying to himself .. What the hell will I do with this cylinder ...with Craig's OCD and being a perfectionist . I can't afford to screw up a bit. This one should be spotless and looking like brand new after assembly
..... HHmmmm , I will drop it into a hydrochloric solution and should be spotless after .. hahahaha
kidding aside , almost there Craig . Looks like spring won't be here and you got a GTE SC300 .
Saying to himself .. What the hell will I do with this cylinder ...with Craig's OCD and being a perfectionist . I can't afford to screw up a bit. This one should be spotless and looking like brand new after assembly
..... HHmmmm , I will drop it into a hydrochloric solution and should be spotless after .. hahahahakidding aside , almost there Craig . Looks like spring won't be here and you got a GTE SC300 .
It's the same way I approach any kind of project-- not just cars.No, I think it'll be into spring still before this is anywhere near done. Once I have the cleaned and assembled head back I will slow down and take a break again other than to ship that and a few other parts to Florida for the assembly later. And I will evaluate and work on the wiring harness here-- I just haven't had time to devote to it yet.
With the exception of engine bearings and a gasket kit I have the bottom end prepped. I still have to drill the GE oil pan turbo drain also. And I probably should order new knock sensors, right? Especially if I'll be using the engine in areas with 91 and sometimes 90 (higher altitude) octane?
....
With the original engine setup, however, I am getting more concerned about the rough starting issue. It is very consistent now. Same exact behavior though-- only at cold startup or after cooling down a bit from full operating temperature. Zero misfires or moments of hesitation during operation. Only once has the problem occurred after startup: when I let the engine idle for about 25 minutes straight waiting to put the rear wheels on a dyno for a smog pre-test a few months back. I shut the engine off and restarted and it fired right back up. It's never done it again since.
Having replaced so many obvious parts already I am still suspecting either the original fuel pump, original fuel ECU or perhaps one of the replaced remanufactured injectors sticking. The problem always clears up before I am able to touch all six injectors with my stethoscope when the engine is starting from cold and has the rough idle. I think I will begin testing them in specific blocks of threes or twos each morning to give myself enough of a time window to positively rule out the good ones. If they all turn out to be good then I can't imagine it being anything else other than the fuel ECU or fuel pump.
I did try the fuel ECU bypass a few months ago but it seemed to make no difference. I think I will try it again just to be sure.
I have that new OEM TT pump. I could just do that and the +12V w/relay mod now if the injectors all check out OK. Have to look up the procedures you guys have laid out for the wiring.
I prefer to leave this issue alone but I also don't want the car to strand me if whatever this is does make something fail.
Stop asking me to fix more things, car! You're getting a whole engine
...
It was also recommended to me at Driftmotion that I might want to look into a steel 1-piece driveshaft to replace my MKIII front and SC300 rear shaft setup since I did have some tight initial spline clearance when it first went in requiring me to remove the rear metal shield on the R154's output area. I haven't had the original symptom related to that in three years so I haven't worried about it but maybe it's sound advice.
Can't do it now but I may well in the new year.
Last edited by KahnBB6; 09-15-16 at 02:05 PM.
09-17-16, 12:16 AM
#287
Pole Position
Glad to see that your project is progressing Craig! Going for a gte block sounds like a good path. Looking forward to following your build!
I wouldn´t mind having driftmotion next door. You lucky b*****d
I wouldn´t mind having driftmotion next door. You lucky b*****d
09-18-16, 04:15 AM
#288
Thank you Lettut! As before it's going at a snail's pace but it's going forward. I like checking in on your MKIV hybrid build as well! Eventually I realized starting from a GTE block turned out to be the only reasonable path for my particular swap
As for having Driftmotion nearby... I'd say I still have to drive an hour to get to them but I know that's nothing compared to shipping from California to Sweden plus duty fees. I'm happy to hear you found a good local shop who could do the standard CT12 rebuild and upgrade for you.
Right now I have two shops: one I can drive to for my cylinder head work and one for my paused engine block work that is over 2,700 miles away ;D
As for having Driftmotion nearby... I'd say I still have to drive an hour to get to them but I know that's nothing compared to shipping from California to Sweden plus duty fees. I'm happy to hear you found a good local shop who could do the standard CT12 rebuild and upgrade for you.
Right now I have two shops: one I can drive to for my cylinder head work and one for my paused engine block work that is over 2,700 miles away ;D
09-27-16, 02:57 AM
#289
I've been doing a lot of fall cleaning lately and organizing parts.
New OEM GTE cylinder head springs, retainers and locks/clips will be delivered soon and will then be driven to Driftmotion to start the head and cam inspection. I already have a set of SuperTech valve stem seals set aside also. The old original lifters will be reused unless any damage is detected during the inspection. The only unknown currently is the condition of the 12 intake and 12 exhaust valves that came with the head completely out of order in less than perfect shape. More delay from the head rebuild depending on how many valves, if any, need to be ordered.
And then the cleaning and inspection for straightness and inspection of the USDM TT cams still needs to happen to determine all the main hardware is in good shape to begin with.
But things are moving along on that front!
I also pulled the trigger on a matching Onyx Black 202 SC400 trunk with the early style spoiler with good paint. Should just bolt on and take to a good wax and buff to wake up the finish. I'll know soon if the pictures were telling the truth or not but I'm confident they were. There are two little edge areas that will need a very small amount of work done at a body shop. Clean trunk though and it will match the car so I am happy
So now I will have a stock 1993 body with a 97+ front bumper and a 1992-1995 SC400 rear wing
I guess it's my attraction to classic muscle car ducktail lines that finally got the better of me
New OEM GTE cylinder head springs, retainers and locks/clips will be delivered soon and will then be driven to Driftmotion to start the head and cam inspection. I already have a set of SuperTech valve stem seals set aside also. The old original lifters will be reused unless any damage is detected during the inspection. The only unknown currently is the condition of the 12 intake and 12 exhaust valves that came with the head completely out of order in less than perfect shape. More delay from the head rebuild depending on how many valves, if any, need to be ordered.
And then the cleaning and inspection for straightness and inspection of the USDM TT cams still needs to happen to determine all the main hardware is in good shape to begin with.
But things are moving along on that front!
I also pulled the trigger on a matching Onyx Black 202 SC400 trunk with the early style spoiler with good paint. Should just bolt on and take to a good wax and buff to wake up the finish. I'll know soon if the pictures were telling the truth or not but I'm confident they were. There are two little edge areas that will need a very small amount of work done at a body shop. Clean trunk though and it will match the car so I am happy
So now I will have a stock 1993 body with a 97+ front bumper and a 1992-1995 SC400 rear wing
I guess it's my attraction to classic muscle car ducktail lines that finally got the better of me
Last edited by KahnBB6; 09-27-16 at 03:08 AM.
11-27-16, 04:02 AM
#290
Yesterday I replaced the NA fuel pump ECU with a new Denso unit and that seems to have solved the rough starting issue, finally. The car seems to be running better as a result.
Since I needed it done and after much struggling with the insanely placed second screw holding it in I was able to get the Mirror Control ECU replaced and... voila. I have working side view mirrors again. I did not bother to replace that awful second screw. Good riddance to the engineer who failed to come up with a better way to get to it.
My 2JZGTE cylinder head is now rebuilt. I gave it new springs and locks and some other bits but most of the original valvetrain was in good shape and was able to be reused. Two exhaust valves had to be replaced but all in all it wasn't too bad with replacement parts. It took the shop a long time because I bought a head that was completely dismantled to begin with.
I'm picking it up this week. Another major chunk of the swap is now out of the way and I can now close up the engine once the short block is rebuilt.
Onward!
Since I needed it done and after much struggling with the insanely placed second screw holding it in I was able to get the Mirror Control ECU replaced and... voila. I have working side view mirrors again. I did not bother to replace that awful second screw. Good riddance to the engineer who failed to come up with a better way to get to it.
My 2JZGTE cylinder head is now rebuilt. I gave it new springs and locks and some other bits but most of the original valvetrain was in good shape and was able to be reused. Two exhaust valves had to be replaced but all in all it wasn't too bad with replacement parts. It took the shop a long time because I bought a head that was completely dismantled to begin with.
I'm picking it up this week. Another major chunk of the swap is now out of the way and I can now close up the engine once the short block is rebuilt.
Onward!
Last edited by KahnBB6; 11-28-16 at 02:12 AM.
11-30-16, 07:35 PM
#294
I completely forgot to take pictures of the head at Driftmotion! I am going to ask if they will send me a couple so I can post them. The head looked beautiful and practically brand new. The cams looked aged but they were all spec'd in there with assembly lube and they had been fully cleaned like everything else. I am having DM package and ship the head to Florida for the later engine assembly.
Speaking of which... I'm not about to jump on the next stage just yet as it is coming up on Christmas but now I will have to find out if my plan to use the brand new stock size Toyota pistons and rings will work.... or if I must go forged. I will present all the hardware to my machine shop, have the right OEM Toyota bearings ordered and see what the builder says about how the cylinders measure to the OEM stock size pistons.
If my gamble at going totally stock will not work according to his math... then I will be looking at probably CP's in whatever alloy is kinder to the rings and cylinder walls.
For anyone following along who is not aware I have confirmed that Toyota does NOT sell any standard overbore versions of the 2JZGTE pistons or rings. Only the original stock bore. There may be extra clearance built into the OEM rings to allow for rebuilds (I have no idea...) but stock is all they have. Only one other company makes a Hypereutectic (high pressure cast piston) for 2JZGTE's is DNJ Engine Components.... however I have not read anything to suggest they are considered as reliable or bulletproof as Toyota's OEM Hypereutectic pistons so I will would consider them.
The reasoning for attempting to go with the OEM Hypereutectic pistons: engine oil control for emissions (since that is one of the major reasons for building this engine configuration)... and more than that... long term engine life
I am still learning as I go but one of the things that concerns me, even if I am building an engine for 100% stock boost up to BPU-ish 15-16 psi, is that forged pistons and the cylinder bores will not last more than 50k-60k miles or so. I want my rebuilt engine to do at least 250k miles or more. In the last seven years of owning my SC I have put 54k miles on the original engine. That is roughly 7,700 miles per year but I've always planned on driving it a bit more from time to time the way I used to once the the GTE has been installed. I've always intended to put a lot of miles on this car and take it all over which is another reason why I'm building for longevity with much more power but not serious high horsepower and serious high boost.
I'll know more once I'm in Florida again and can present everything to my machinist to see what it all measures out to. Hopefully I will get lucky!
Last edited by KahnBB6; 11-30-16 at 07:39 PM.
12-01-16, 01:00 AM
#295
A minor segue that is getting ahead of myself but here's a bit of what I've been researching for the second time about forged aftermarket pistons:
This one from a 2004 post by Poggie on Supraforums:
http://www.supraforums.com/forum/sho...=1#post1641356
This one from a 2004 post by Poggie on Supraforums:
http://www.supraforums.com/forum/sho...=1#post1641356
One should be careful in ones selection when buying forged aftermarket pistons. There are basically two brands, so to speak, of forged pistons. Those with a Silica content lower than 1% and those with a silica content Silica content above 12 %.
Silica content determines the hardness and growth of the piston. High Silica content pistons allows you to run smaller clearances but they are softer, expand less and are not really made for high boost turbo applications.
A piston with a Silica content less than 1% would be a good recommendation for a high boost, high horsepower engine.
Another factor would be ringland strength and flatness. Strong ringlands is always a must and the flatter the ringland is the better the ring to piston seal.
Silica content determines the hardness and growth of the piston. High Silica content pistons allows you to run smaller clearances but they are softer, expand less and are not really made for high boost turbo applications.
A piston with a Silica content less than 1% would be a good recommendation for a high boost, high horsepower engine.
Another factor would be ringland strength and flatness. Strong ringlands is always a must and the flatter the ringland is the better the ring to piston seal.
12-01-16, 09:35 PM
#296
I just found this article. Great. If nationwide E15 is to move forward at 99% of the fuel pumps nationwide I may need to do an E85/FlexFuel conversion with a pricey aftermarket ECU on top of the swap and plan to have even lower fuel economy and higher baseline boost to compensate at E15.
I know the stock SC300 fuel system and MKIV TT fuel system will not survive well indefinitely in stock form if run on anything higher than E10.
Sigh...
http://arstechnica.com/business/2016...into-gasoline/
I know the stock SC300 fuel system and MKIV TT fuel system will not survive well indefinitely in stock form if run on anything higher than E10.
Sigh...
http://arstechnica.com/business/2016...into-gasoline/
12-10-16, 02:32 PM
#297
The rebuilt GTE head and some other parts are about to join the rest of the engine parts and I'll soon be getting into some work on prepping various bits over the holidays (drilling the oil pan for turbo return, getting dirty aluminum parts cleaned, having valve covers cleaned and repainted, etc.) and possibly getting the block assembly started.
I promise I will get some pictures to post soon so that this isn't a text-only build thread.
The core twin turbo assembly and wiring harness I'm not dealing with just yet in CA... but I am weighing what to do about my 3.769:1 TT Auto ring and pinion.
I made a very deliberate choice six years ago to have my TT Auto LSD diff not only rebuilt but switched out to a 4.272:1 NA Auto ratio. At the time I wasn't even sure if I was going to go 2JZGTE and since it was a stock ratio for early model Supra MKIV NA 5-speeds it made it an essentially factory configuration in a different car. I've loved the car's willingness to rev and the available torque in each gear. Highway cruising has always had to be kept to a reasonable, legal speed limit to keep the fuel economy down to a respectable 3000 RPM or so.
From the beginning that was a tradeoff and I knew full well what I was getting into and I've been pleased with the aggressive final drive ratio in an NA car.
However since the car will finally be going GTE it makes sense to consider getting that diff rebuilt a second and final time with its original ring and pinion which have been wrapped up in A/C storage.
I can do this before the swap is finished and run the 3.769 TT Auto ratio on my stock 220HP NA engine... or I can do it a little after the swap is finished and initially run my 2JZGTE with the 4.272 ratio. Out in L.A. I have two excellent driveline shops I trust for top notch differential work and all the parts and car are here. Downtime would be minimal. I am sure I could find a good driveline shop on the east coast as well. Getting it done right is not a problem.
I'm just not sure if running the 3.76 against an NA engine would be tolerable, especially for steep uphill climbs or high elevation drives (5000 feet has not been uncommon for me sometimes). Certainly it would not be ideal and it would make the car even slower on acceleration but functionally I wonder if it would simply be too much of a drop to even work properly. I know what the ratio changes do on paper and I have experience with the effects of going to a more aggressive short ratio but I am concerned about the 3.769 ratio being far too low for the non-turbo engine to function in a healthy way. I hope I am wrong about this.
To educate myself I did a little research on 2002-2005 IS300 5-speed M/T's. These run a 215hp/218lb-ft version of the 2JZ-GE VVT-i (SAE revised their rating system around that time), a W55 5-speed gearbox with aggressive ratios, a 3.727:1 final drive ratio with an LSD and a 215/45-17 OE tire.
I did some calculations from these links:
https://en.wikipedia.org/wiki/Toyota_W_transmission
https://en.wikipedia.org/wiki/Toyota_R_transmission
https://tiresize.com/height-calculator/
http://www.csgnetwork.com/multirpmcalc.html
http://www.apexgarage.com/tech/gear_ratios.shtml
And I specified the stock 6,800RPM redline.
Since Toyota/Lexus did offer the IS300 M/T with a 3.7xx ratio from the factory (probably to meet CAFE) it suggests to me that the combination will work.
Here's what I got for the speeds achievable in each gear for the IS300 M/T:
IS300 M/T
W55 5-speed
1st: 3.566 (37 mph)
2nd: 2.056 (65 mph)
3rd: 1.384 (96 mph)
4th: 1.00 (134 mph)
5th: 0.850 (157 mph)
Final Drive: 3.727:1
OE Tire Size: 215/45-17 (24.6” dia)
And here is what my car in its current state of tune calculates out to. Note that I list a 255/40-17 tire which is my current one. This will change to a 275 soon.
SC300 M/T Non-Turbo
R154 5-speed
1st: 3.251 (36 mph)
2nd: 1.955 (61 mph)
3rd: 1.310 (90 mph)
4th: 1.00 (118 mph)
5th: 0.753 (157 mph)
Final Drive: 4.272:1
Tire Size: 255/40-17 (25” dia)
And here is what my calculations come out to for my car with the 275/40-17 rear tires I'll be switching back to soon, plus the 3.769:1 final drive ratio. Nothing to write a post about if there is turbo boost but in the interim with just the stock NA engine I wonder how different this would feel in everyday use compared to a stock IS300 5-speed M/T with the 3.7 diff.
SC300 M/T Non-Turbo
R154 5-speed
1st: 3.251 (42 mph)
2nd: 1.955 (71 mph)
3rd: 1.310 (105 mph)
4th: 1.00 (138 mph)
5th: 0.753 (183 mph)
Final Drive: 3.769:1
Tire Size: 275/40-17 (25.7” dia)
I won't be doing anything with the differential right away but this might be what I get into at the start of the new year well prior to my GTE engine being finished. And thus I might take the car across a range of driving situations and elevation changes with that 3.769 ratio and no boost for a while.
I know it would then be a slow car but from a functional and safety perspective in terms of making the original NA engine work even harder what do you guys think?
I promise I will get some pictures to post soon so that this isn't a text-only build thread.
The core twin turbo assembly and wiring harness I'm not dealing with just yet in CA... but I am weighing what to do about my 3.769:1 TT Auto ring and pinion.
I made a very deliberate choice six years ago to have my TT Auto LSD diff not only rebuilt but switched out to a 4.272:1 NA Auto ratio. At the time I wasn't even sure if I was going to go 2JZGTE and since it was a stock ratio for early model Supra MKIV NA 5-speeds it made it an essentially factory configuration in a different car. I've loved the car's willingness to rev and the available torque in each gear. Highway cruising has always had to be kept to a reasonable, legal speed limit to keep the fuel economy down to a respectable 3000 RPM or so.
From the beginning that was a tradeoff and I knew full well what I was getting into and I've been pleased with the aggressive final drive ratio in an NA car.
However since the car will finally be going GTE it makes sense to consider getting that diff rebuilt a second and final time with its original ring and pinion which have been wrapped up in A/C storage.
I can do this before the swap is finished and run the 3.769 TT Auto ratio on my stock 220HP NA engine... or I can do it a little after the swap is finished and initially run my 2JZGTE with the 4.272 ratio. Out in L.A. I have two excellent driveline shops I trust for top notch differential work and all the parts and car are here. Downtime would be minimal. I am sure I could find a good driveline shop on the east coast as well. Getting it done right is not a problem.
I'm just not sure if running the 3.76 against an NA engine would be tolerable, especially for steep uphill climbs or high elevation drives (5000 feet has not been uncommon for me sometimes). Certainly it would not be ideal and it would make the car even slower on acceleration but functionally I wonder if it would simply be too much of a drop to even work properly. I know what the ratio changes do on paper and I have experience with the effects of going to a more aggressive short ratio but I am concerned about the 3.769 ratio being far too low for the non-turbo engine to function in a healthy way. I hope I am wrong about this.
To educate myself I did a little research on 2002-2005 IS300 5-speed M/T's. These run a 215hp/218lb-ft version of the 2JZ-GE VVT-i (SAE revised their rating system around that time), a W55 5-speed gearbox with aggressive ratios, a 3.727:1 final drive ratio with an LSD and a 215/45-17 OE tire.
I did some calculations from these links:
https://en.wikipedia.org/wiki/Toyota_W_transmission
https://en.wikipedia.org/wiki/Toyota_R_transmission
https://tiresize.com/height-calculator/
http://www.csgnetwork.com/multirpmcalc.html
http://www.apexgarage.com/tech/gear_ratios.shtml
And I specified the stock 6,800RPM redline.
Since Toyota/Lexus did offer the IS300 M/T with a 3.7xx ratio from the factory (probably to meet CAFE) it suggests to me that the combination will work.
Here's what I got for the speeds achievable in each gear for the IS300 M/T:
IS300 M/T
W55 5-speed
1st: 3.566 (37 mph)
2nd: 2.056 (65 mph)
3rd: 1.384 (96 mph)
4th: 1.00 (134 mph)
5th: 0.850 (157 mph)
Final Drive: 3.727:1
OE Tire Size: 215/45-17 (24.6” dia)
And here is what my car in its current state of tune calculates out to. Note that I list a 255/40-17 tire which is my current one. This will change to a 275 soon.
SC300 M/T Non-Turbo
R154 5-speed
1st: 3.251 (36 mph)
2nd: 1.955 (61 mph)
3rd: 1.310 (90 mph)
4th: 1.00 (118 mph)
5th: 0.753 (157 mph)
Final Drive: 4.272:1
Tire Size: 255/40-17 (25” dia)
And here is what my calculations come out to for my car with the 275/40-17 rear tires I'll be switching back to soon, plus the 3.769:1 final drive ratio. Nothing to write a post about if there is turbo boost but in the interim with just the stock NA engine I wonder how different this would feel in everyday use compared to a stock IS300 5-speed M/T with the 3.7 diff.
SC300 M/T Non-Turbo
R154 5-speed
1st: 3.251 (42 mph)
2nd: 1.955 (71 mph)
3rd: 1.310 (105 mph)
4th: 1.00 (138 mph)
5th: 0.753 (183 mph)
Final Drive: 3.769:1
Tire Size: 275/40-17 (25.7” dia)
I won't be doing anything with the differential right away but this might be what I get into at the start of the new year well prior to my GTE engine being finished. And thus I might take the car across a range of driving situations and elevation changes with that 3.769 ratio and no boost for a while.
I know it would then be a slow car but from a functional and safety perspective in terms of making the original NA engine work even harder what do you guys think?
Last edited by KahnBB6; 07-30-22 at 02:40 AM. Reason: Typo fix
12-11-16, 04:32 AM
#298
Craig , good progress . Slow but sure 
and doing it right the first time !
If I am not mistaken you have an R154 . Between your 3.76 and 4.27 ring and pinion, the former will be the better one for you trans.
You choose your diff ratio based on your trans and not because of your engine whether its GTE or GE.
Your trans gearing should match your final drive gearing but also taking into consideration the use of the car of course.
keep it up buddy ! I love your being meticulous wanting always to do it right for our beloved SC.
You are one truly SC enthusiast . One who modifies the car for the best . Kudos !
and doing it right the first time !If I am not mistaken you have an R154 . Between your 3.76 and 4.27 ring and pinion, the former will be the better one for you trans.
You choose your diff ratio based on your trans and not because of your engine whether its GTE or GE.
Your trans gearing should match your final drive gearing but also taking into consideration the use of the car of course.
keep it up buddy ! I love your being meticulous wanting always to do it right for our beloved SC.
You are one truly SC enthusiast . One who modifies the car for the best . Kudos !
12-11-16, 04:58 AM
#299
Thanks Gerry! I just want to make sure I won't harm anything as I do each major change to the car in stages. This is the last major one before it all comes down to the engine.
Well... it has been recommended I also invest in a one-piece steel driveshaft. I may do that later.
Yes, I have had a rebuilt and upgraded R154 in the car since 2013. I have had the 4.27 Torsen LSD in the car since 2011 (when I still had the original W58). The 3.76 ratio is going in no matter what. Absolutely no question about that. This is just me wondering how effective the 3.76 ratio will be if I swap it in while I'm still running the GE engine especially if I have to climb hills or go into high elevation sometimes.
To date the 4.27 ratio has worked well with both the W58 and R154 but it's still a ratio best suited for W58's. Now, however, it is close to the time to consider changing it out in preparation for twin turbos.
I also won't mind the better highway fuel economy with the 3.76 If I were staying NA I would not do it but I am not staying NA. It will make my SC300 slower to accelerate with no boost but I just want to be sure I will not over-stress the stock GE engine by doing this.
I feel like seeking out a 2002-2005 IS300 with the factory W55 5-speed M/T and 3.7 ratio for sale at a used dealer and trying it out to get a sense of how that setup feels in factory tune even though I know my setup will still have slightly longer overall gearing.
...
I will not tackle diff ratios until the new year. Getting started on the new engine assembly is the first priority soon.
Well... it has been recommended I also invest in a one-piece steel driveshaft. I may do that later.
Yes, I have had a rebuilt and upgraded R154 in the car since 2013. I have had the 4.27 Torsen LSD in the car since 2011 (when I still had the original W58). The 3.76 ratio is going in no matter what. Absolutely no question about that. This is just me wondering how effective the 3.76 ratio will be if I swap it in while I'm still running the GE engine especially if I have to climb hills or go into high elevation sometimes.
To date the 4.27 ratio has worked well with both the W58 and R154 but it's still a ratio best suited for W58's. Now, however, it is close to the time to consider changing it out in preparation for twin turbos.
I also won't mind the better highway fuel economy with the 3.76
If I were staying NA I would not do it but I am not staying NA. It will make my SC300 slower to accelerate with no boost but I just want to be sure I will not over-stress the stock GE engine by doing this.I feel like seeking out a 2002-2005 IS300 with the factory W55 5-speed M/T and 3.7 ratio for sale at a used dealer and trying it out to get a sense of how that setup feels in factory tune even though I know my setup will still have slightly longer overall gearing.
...
I will not tackle diff ratios until the new year. Getting started on the new engine assembly is the first priority soon.
12-14-16, 12:21 PM
#300
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I am going to check SupraTico's thread again because I am pretty sure he used the GE VVT-i oil pump with a USDM TT ECU. But I now have to check to be sure he wasn't using an aftermarket ECU that could have changed to either 24 tooth or 36 tooth trigger.
What do you think? :/
What do you think? :/
Regards,
Tony